PURPOSE: To enable the connection of electrodes and lead frames to be surely executed so as to enhance the joint strength of a joint part.

CONSTITUTION: The multilayered lead frame is constituted by joining the lead frames 5, a power source plane 6 and a ground plane 7 in multiple layers via electrical insulating layers 8 held between the layers, extending and providing electrodes 9 for connection positioned on the power source leads of the lead frames and the ground plane from the outer edges of the power source plane 6 and the ground plane 7 and resistance welding the electrodes to the power source leads and the ground lead, respectively. The joint parts of the electrodes and the lead frames to which the electrodes are joined of the above-mentioned lead frame are subjected to plating, such as silver plating, tin plating or nickel plating, provided on both or either of the electrodes 9 and the lead frames 5, by which the electrodes and the lead frames are resistance welded.